java web 文件上传问题

package com.whw.action;

import java.io.File;
import javax.servlet.ServletContext;
import org.apache.commons.io.FileUtils;
import org.apache.struts2.util.ServletContextAware;
import com.opensymphony.xwork2.ActionSupport;

public class UploadAction extends ActionSupport implements ServletContextAware {

private static final long serialVersionUID = 1L;
private File upload;// 实际上传文件
private String uploadContentType; // 文件的内容类型
private String uploadFileName; // 文件 名称
private String fileCaption;// 上传文件时的备注
private ServletContext context;

public String execute() throws Exception {

try {

String targetDirectory = context.getRealPath("/upload");
String targetFileName = fileCaption+uploadFileName;
File target = new File(targetDirectory, targetFileName);
FileUtils.copyFile(upload, target);
setUploadFileName(target.getPath());//保存文件的存放路径
} catch (Exception e) {
addActionError(e.getMessage());
return INPUT;
}
return SUCCESS;

}

public String getFileCaption() {
return fileCaption;
}

public void setFileCaption(String fileCaption) {
this.fileCaption = fileCaption;
}

public File getUpload() {
return upload;
}

public void setUpload(File upload) {
this.upload = upload;
}

public String getUploadContentType() {
return uploadContentType;
}

public void setUploadContentType(String uploadContentType) {
this.uploadContentType = uploadContentType;
}

public String getUploadFileName() {
return uploadFileName;
}

public void setUploadFileName(String uploadFileName) {
this.uploadFileName = uploadFileName;
}

public void setServletContext(ServletContext context) {
this.context = context;
}

}